Yup. Time's money. You can't make any more of it, buy any more of it, you never know how much there is left and the meter's runnin'. It's how I grew up in the midwest, anyway. This 'tude doesn't seem to be as prevalent as idjits doin' 50 in the left lane yakkin' on their cell phones in the Pacific Northwest, however. Anybody asks how I am, I automatically think, "What'r ya writin' a book? You my doctor?"
I like to acknowledge the EXP AAgent by name, but assume they don't want to burn up a lot of time either (as there are calls holding in the queue), so generally I'm off and running with what needs to get done. A sincere thank you is automatic at the end of every call, though...IMHO there's always time to acknowledge appreciation for someone's efforts...even if it is "their job".